Methods of and apparatus for conditioning the uppers of pulled-over shoes



Feb. 26, 1957 M. MAESER ET AL METHODS OF AND APPARATUS FOR CONDITIONING THE UPPERS OF PULLED-OVER SHOES 3 Sheets-Sheet 1 Filed Dec. 16, 1954 All! I I Inventors John LIB/"a oha Mz'et/I Maeser B Feb. 26, 1957 M. MAESER ETAL METHODS OF AND APPARATUS FOR CONDITIONING THE UPPERS OF PULLED-OVER SHOES 3 She ets$heet 2 Filed Dec. 16; 1954 Hzglz Hequen Oscillator [77 I) e n tors John J B/"Ophy 1957 M MAESER ETAL 2,782,431

METHODS OF AND APPARATUS FOR CONDITIONING THE UPPERS OF PULLED-OVER SHOES Filed Dec. 16, 1954 3 Sheets-Sheet 3 x Inventors c/ohrz 'cffirophy M'eth aeser 5 J aired te Pa ifi o 'METHODS OF AND APPARATUS FOR CONDITION- ING THE UPPERS OF PULLED-OVER SHOES Mieth Maeser, Beverly, and John I. Brophy, Salem, Mass, assignors to United ShoeMachinery Corporation, Flen1- ington, N. .L, a corporation of New Jersey Application December 16, 1954,Serial No. 475,712

4 Claims. (c1. 12-1 This inventionrelates to a method .of and apparatus for conditioning selected portions of the upper of a pulledsolvent treatment. 'In many cases, the vicissitudes of shoe factory operationsprevent the shoe from being lasted before the stiffener blank has-rehardened and accordingly it is common to provide as an adjunct of the lasting processes, a resoftening step which is'usually accomplished by 'subjectingthe selected portion of the shoe to some form of heat, as for example by the use of a toe steamer. Such a'conditioning step is also advantageous even where no thermoplastic box tee is employed in order to temper the leather for the lasting operation.

A toe steamer comprises a chamber in which the toe of a pulled-over shoe may be subjected to an atmosphere of hot vapor laden air. Because of the relatively low temperature of the shoe toe at the start of the operation,

water is rapidly condensed from this atmosphere upon the upper so that, because of the large value of the latent heat of vaporization of water, a large amount of heat is quickly supplied to the exterior of the upper. The consequent rise in the temperature of the surface of the upper reduces the rate of condensation progressively until'the temperature of the upper rises above the dew point at which time further heatingof the interior portions of the upper is provided only by the convection heat supplied to the exterior of the upper and transferred therethrough.

Given sufficient time, the upper, with its thermoplastic stiffener blank incorporated therein will be conditioned satisfactorily for lasting. However, certain considerations have made efforts 'to reduce the time required for such conditioning desirable. is the time-temperature sensitivity of leather. Another consideration is the economic advantage inherentin reducing the time required for performing shoe making operations. This is particularly important where the step is to be performed as an adjunct to a machine having a short operating time cycle such as an automatic toe lasting machine. This shortening of time has the effect of reducing the number of shoes in process, which shoes commonly have to be maintained in a predetermined One of these considerations To this end and in accordance with a feature of the invention, a method of and apparatus for so conditioning uppers is provided wherein the upper is first subjected to an atmosphere of hot vapor laden air, thereby to receive the benefit of heat transfer by condensation, and thereafter, for example after the water droplets have been absorbed by the leather which happens very rapidly, the upper is subjected to a high-frequency alternating electric field, established between toe electrodes in the illustrative embodiment, further to raise the temperature of the upper materials by dielectric heatwhich, as is well known, does not depend upon heat transfer from the exterior of the shoe to raise the temperature of the interior portions.

In accordance with another feature of the invention an oscillator supplying the electrodes with high-frequency electric energy is controlled by a time delay circuit adapted to be initiated by the act of the operator in positioning the shoe for conditioning so that after the expiration of a predetermined lag interval, the high-frequency energy will be applied to the electrodes for a predetermined heating interval without further act on the part of the operator.

Other features and advantages of the invention will be apparent from the detailed description hereinafter given, taken together with the drawings in which:

Fig. l is a front view of an apparatus embodying the present invention;

Fig. 2 is a side elevation partly in section of the apparatu shown in Fig. 1;

Fig. 3 is a side elevation greatly enlarged of an electrode assembly employed in the apparatus shown in Fig. l; and

Fig. 4 is a plan view of the electrode assembly shown in Fig. 3 and on the same scale.

The apparatus of the present invention is in many respects similar to a shoe part conditioning apparatus disclosed in United States Letters Patent No. 2,488,533, issued November 22, 1949, on an application in the name of Meith Maeser et a1. Accordingly, the aforesaid patent may be referred to for particularized details of the source of hot vapor laden air employed in the apparatus of the present invention.

The present apparatus thus comprises a base 10 and a shoe treating cabinet 12 which is secured to the top of the base by screws one of which is indicated by the reference numeral 14 in Fig. 2. Hot vapor laden air is supplied to the cabinet 12 by a closed boiler 16 which is mounted on a shelf 18 located in the lower portion of the base 10. The boiler 16 contains a body of water supplied through a pipe 20, the water being heated to a desired temperature by an immersion heater 22. The temperature of the water is controlled by a thermostatic bulb 24 which is connected through a tube 26 to a thermostat 28.

To accelerate the transfer of vapor from the water to the conditioning chamber, the boiler is provided with means for bubbling compressed air through water. This means consists of an air pump 30 driven by a motor 32 through a belt 34. Air from the pump passes through a pipe 35 to a filter 36 and thence through a pipe 38 to a manifold (not shown) located in the bottom of the boiler 16, the compressed air escaping from the manifold through small perforations. The resulting hot vapor laden air is supplied to a superheating unit 40, fully described in the above patent, by a pipe 44 and thence to the conditioning chamber.

This chamber in the conditioning cabinet 12 is formed with the unit as a floor, insulated metallic side walls 46, and a roof 48 provided with electric heater units 50 (Fig. 2), together with front and rearpanels 52 and 54, respectively. The front panel 52 is formed with an opening 56 for admitting the toe end of a shoe to the heating cabinet. Supported on the unit 40 at the for- Ward end of the heating chamber is a U-shaped pipe frame 58 attached to the outlet of the superheating unit 40 by an apertured block 60 so that the hot vapor laden air is supplied directly to the pipe frame to issue through a'series of holes in the pipe to surround the toe of an .operatively positioned shoe with an atmosphere of such hot air. I

The electrode arrangement provided in accordance with the present invention for establishing a-high-frequency electric field in the toe end of the shoe is generallysimilar to the electrode arrangement disclosed in 'United States Letters Patent No. 2,528,491, issued November 7, 1950, on an application in the name of Robert W. Bradley, et al. and illustrated in Figs. 3, 4 and thereof. However, since the shoe is to be treated after the pulling-over operation but prior to the lasting operation, so that the lasting-margin projects from the bottom edge of the last in somewhat irregular fashion, and since this margin, as well as the adjacent areas, must be included in the electric field, the electrodes have been slightly modified, firstly to provide a recess to receive the margin while supporting the shoe, and secondly, to adjust the electric field pattern to the changed circumstances.

Thus as in the above Bradley et al. patent, the electrodes are mounted on a stand 64 secured to the superheating unit 40 through a mounting plate 66 attached to the unit 40 by screws 68 which pass through spacing collars 70. A plastic slab 72 is attached to the stand 64 and at the top edge of the slab is pivoted a hinge portion 74. Hinged on the portion 74 are two elongated metal arms 76 which form the lower electrode, the arms being set into relatively deep rabbets 75 in flat plastic bottom pieces 77 which also carry plastic spacers 78. The arms 76 are inwardly urged by springs 80 which bear against a portion of the spacers 78.

The upper electrode 82 attached to plastic spacers 83 is pivoted between two uprights 84 attached to the hinge portion 74 and is urged downwardly by a spring 86 to engage the toe of the shoe. A shielded spring assembly 88 serves yieldingly to hold the electrode assembly in a convenient attitude for inserting a shoe between the electrodes. Further details of construction of this electrode assembly may be found in the aforesaid Bradley et a1. patent.

To the rear of the heating cabinet is disposed a highfrequency oscillator 90 which is connected to the electrodes by leads 92. The oscillator is arranged to be supplied with line voltage through a cable 94 and to supply high-frequency energy to the electrodes a predetermined interval after a connection is established between two control terminals 96. It is highly desirable to provide a lag interval between the time the shoe toe is inserted in the vapor chamber and the time the electric 'field is applied, for if the field is applied too soon, heating Accordingly, a first or lag interval timer 98 is connected between the control terminals 96 and a second or heating timer 99 which in turn is arranged to operate a relay switch controlling the application of plate voltage to the oscillator when the timer 98 has timed out.

Attached to the base of the machine is a block 100 supporting a heel rest 102 adapted to receive the heel end of a shoe and to cooperate with the electrode assembly to support the shoe in operative position. The rear of the rest 102 is hinged to the rear of the block 100 while the front end of the rest is yieldingly supported a little above the front of the block upon the operating plunger 104 of a switch 106 connected by a cable 108 to the control terminals 96. Thus the switch 106 is arranged for closure of its contacts by disposition of a shoe in operative position.

In operation with the oscillator connected with the power line and warmed-up and with the hot vapor apparatus running to force its output through the orifices of the pipe frame 58, the apparatus is ready for use. The operator may then take a pulled-over shoe and insert its toe through the opening 56 and between the upper and lower electrodes. He then allows the heel end of the shoe to settle in the heel rest 102 and to operate the switch 106. Thereupon he may pay no further attention to the shoe until he is ready for it. Meanwhile, closure of the switch 106 starts the lag timer which at the end of a predetermined delay will operate the heating timer to cause the oscillator to supply high-frequency energy to the electrodes for a predetermined heating interval after which the oscillator is again shut off.

Thus We have provided a method and apparatus employing a high-frequency electric field together with hot vapor laden air for conditioning a shoe upper, in which the field is applied after an initial lag period to reduce the time required for conditioning the shoe upper for lasting without adversely affecting the mulling of the upper leather, thereby providing all benefits which accrue fromsuch a shortened shoe manufacturing operation.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

l. The method of conditioning a shoe upper containing a thermoplastic stiffener blank to place it in condition for lasting, comprising the steps of subjecting a selected portion of the shoe upper containing such a stiffener blank to hot vapor laden air and thereafter, and while said portion is being subjected to said air, subjecting said portion to a high-frequency alternating electric field.

2. The method of conditioning the upper of a pulledover shoe to prepare said upper for lasting comprising the steps of subjecting said upper to hot vapor laden air and thereafter subjecting said upper while still hot to a high-frequency alternating electric field.

3. The method of conditioning a portion of a shoe upper to prepare it for lasting, comprising the steps of subjecting said portion. to an atmosphere of hot vapor laden air and after the temperature of the exterior of said portion has risen above the dew point of said atmosphere additionally subjecting said upper to a highfrequency alternating electric field.

4. Apparatus for conditioning shoe parts for lasting, comprising in combination a chamber having a restricted opening adapted to receive the toe end of a pulled-over shoe, means for supporting a shoe with its toe projecting through said opening and into said chamber, electrodes arranged within said chamber to establish an electric field through marginal portions of the upper of said shoe, an oscillator operable to energize said electrodes, means for supplying hot vapor laden air to said chamber, switch means adapted and arranged to be actuated from a first position into which it is normally biased to a second position by disposition of a shoe in operating position with respect to said supporting means, and connections between said switch means and said oscillator including time delay means whereby upon movement of said switch means to said second position and after the expiration of a lag interval said oscillator is caused to energize said electrodes for a predetermined heating interval.

References Cited in the file of this patent UNITED STATES PATENTS 1,326,112 Stubbs Dec. 23, 1919 1,358,695 'Baynard et al Nov. 16, 1920 1,710,287 Baynard Apr. 23, 1929 2,283,306 Andrews May 19, 1942 2,528,491 Bradley et al Nov. 7, 1950 2,666,130 Bradley Jan. 12, 1954 

